Tow truck system

ABSTRACT

The intersection between the main track along which vehicles are pushed and a non-powered spur track is controlled by a switch device. An endless drive associated partially w1th the main track and the spur track causes vehicles to move along the spur track by contacting a portion of the vehicle as it is moving along the main track.

United States Patent [191 Reiche [451 Nov. 13, 1973 TOW TRUCK SYSTEMInventor: Hans Joachim Reiche, Hummelweg,

Germany Assignee: Fromme, Foerderanlagen wetzrer oeraiasy Filed: Oct. 5,1971 App]. No.: 186,636

U.S. Cl 104/172 BT, 104/172 S Int. Cl. B65g 17/20, 865g 17/38 Field ofSearch 104/172 BT, 172 R,

References Cited UNITED STATES PATENTS Burrows 104/172 BT 2,949,8628/1960 Klamp l04/l72 BT Primary Examiner-Drayton E. HoffmanAttorney-Seidel, Gonda & Goldhammer [57] ABSTRACT The intersectionbetween the main track along which vehicles are pushed and a non-poweredspur track is controlled by a switch device. An endless drive associatedpartially with the main track and the spur track causes vehicles to rnove along the spur traek By contacting a portion of the vehicle as itis moving along the main track.

11 Claims, 6 Drawing Figures PATENIEDNUV 13 I975 SHEET 10F 2 60 can 11/7Ill/1"! Fig. 3

TOW TRUCK SYSTEM This invention is directed to a tow vehicle systemhaving a main track portion wherein vehicles are driven by some type ofconveyor means. Associated with the main track at spaced pointstherealong, there are provided non-powered spur tracks. The movement ofthe conveyed vehicle along the main track is utilized to move thetransferred or diverted vehicles for movement along the spur track.

It is known in systems proposed heretofore to have a spur track providedwith an endless drive chain meshed with the main conveyor chain. Thecontinuous pushing of the main spur conveyor by the main conveyor is anunnecessary strain on the latter. In addition, the continuous driving ofthe spur conveyor is unnecessary unless vehicles are disposed along thespur line.

In accordance with the present invention, the conveyor which extendsalong the spur track and partially along the main track is non-powered.Means are provided for intermittently moving the non-powered spurconveyor. Such means includes arms at spaced points along the spurconveyor which extend it to a position wherein they may be driven by aportion of a tow vehicle such as the tow pin. The spur conveyor extendsalong the main track for a length which is at least as long as thevehicles moving along the main track. The spur conveyor has arms thereonin pairs with the distance between the pairs of arms being at least onevehicle length.

It is an object of the present invention to provide a novel tow trucksystem wherein a non-powered spur intermittently utilizes the power of amain conveyor by contact with a portion of vehicles moving along themain conveyor immediately preceeding the intersection of the main trackand the spur track.

For the purpose of illustrating the invention, there is shown in thedrawings a form which is presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIG. 1 is a partial plan view of a system in accordance with the presentinvention and illustrates the intersection of a spur track and a maintrack.

FIG. 2 is a section of the main drive conveyor and the non-powered spurconveyor where they overlap.

FIG. 3 is an elevation view of several lengths of the main driveconveyor of FIG. 2 with a tow pin on a vehicle pushing an arm on thespur conveyor.

FIG. 4 is a partial plan view of a second embodiment of a systemconstructed in accordance with the present invention.

FIG. 5 is a sectional view of the embodiment of the inventionillustrated in FIG. 4.

FIG. 6 is a plan view of the device illustrated in FIG.

Referring to the drawing in detail, wherein like numerals indicate likeelements, there is shown in FIG. 1 a portion of a tow truck system inaccordance with the present invention. The intersection of the mainconveyor track 1 and the spur track 3 is controlled by a switch 2. Forpurposes of description, the system of the present invention is mountedin a floor flush with the upper surface of floor 4.

A spur conveyor chain of the non-power type extends partially along thespur track 3 and extends partially along the main track 1. In FIG. 1,the vehicles 10 are moving from left to right under the influence of themain conveyor 5.

The spur conveyor 6 extends around sheaves 7 and 8. Sheave 7 issufficiently far in advance of the switch 2 so as to extend for adistance which is in excess of the length of the vehicles 10. Theconveyor 6 is provided at spaced points therealong with sets of arms 9.The sets of arms 9 include a first arm 9a and a second arm 9b which arelinearly spaced from one another along the conveyor 6 by a gap. The gapbetween the arms 9a and 9b is sufficient so that the tow pin 1011 on thevehicles will engage the arm 9a without contacting arm 9b. Thereafter,as arm 9b comes around the sheave 7, it will be positioned behind thetow pin 10a by a distance of approximately 6 inches.

The vehicle 10 has a tow pin 10a which depends downwardly and extendsthrough a main slot so that the lower end of the tow pin is engaged by aface 5a on the main conveyor 5.

When a tow pin 10a engages the arm 9a, it drives the spur conveyor 6over a distance corresponding approximately to about twice the length ofthe vehicles 10. When a vehicle 10 appropriately trips the switch 2, orthe switch 2 is activated in any conventional manner, the vehicle willthen be transferred from the main track to the spur track 3. At thistransfer point, the vehicle 10 will coast into the spur track 3 and thenstop since the spur track 3 is non-powered. The next vehicle which comesalong the main track 1 will engage an arm 9a and move the spur conveyor6 for a short distance corresponding approximately to twice the lengthof a vehicle. This will cause the transferred or diverted vehicle tomove further on down the spur track 3. Movement of the vehicles alongspur track 3 is accomplished by contact between arm 9b on the spurconveyor 6 and the tow pin on the vehicle 10. Eventually the vehiclesalong the spur track 3 will lose contact with the conveyor 6 as thevehicles move beyond the guide sheave 8 and continue along the spurtrack 3 for any desired operation such as storage, loading, unloading,etc.

Thus, it will be seen that the spur conveyor 6 is intermittently drivenby contact with a portion of vehicles moving along the main track. Inthis manner, continuous driving and power necessary for such continuousdriving of the spur conveyor is eliminated. Also, contact between apower driven vehicle moving along the main track 1 and the rear end ofthe diverted vehicle is avoided.

A second embodiment of the invention is illustrated in FIGS, 4, 5 and 6.As seen in those Figures, the second embodiment comprises an overheadconveyor system utilizing an overhead conveyor for driving the trucks.

At the spur, an endless chain 21 which functions as a loop couplingmember is mounted for rotation about sheaves 22 and 23. The chain runsadjacent the shunt conveyor track portion 20. The endless chain 21 isprovided with a plurality of outwardly directed dogs 24 which engageguiding rollers 25b which are supported by the trucks 25. Each truck 25supports one set of guiding rollers at each end.

As seen in FIG. 5, a drive conveyor 26 having a depending member 27 isoperative to engage the portion of the member supporting the guidingrollers 25b to move truck 25 into the switching zone. As seen in FIG. 5,the guiding rollers 25b and 25b are provided with upwardly anddownwardly directed engaging members. The upwardly directed engagingmember is for engagement with members 27 on the drive conveyor. Thedownwardly directed member is engaged by dogs 24 in the area adjacentchain 21.

The dogs 24,, 24 24 24 are shown in detail in FIG. 6. Each of theengagement dogs 24 comprises a generally flat plate pivotally mounted onendless chain 21 for rotation in a horizontal plane. The extent of itsrotation is limited by an arcuate slot formed therein. A heavy dutyspring 24a biases the dog so that it normally overlies the conveyortrack 20. It is constrained from further rotation by virtue of a raisedpin which projects a short distance through the other end of the slot.

Normally, the dogs 24 are in the position illustrated. However, ifsubjected to a heavy load such as when the track is jammed, the platerotates out of the path of the conveyor section against the force ofspring 24a.

The spacing between adjacent dogs is at least the length of one of thetrucks 25. The total number of dogs is such that when one of the dogs isengaged by an arriving truck 25b moving into truck portion 20, anotherdog, such as dog 24 is in a position where it may move into the positionof the first dog 24,. This occurs before the chain 21 comes to rest.

As the trucks 25 are moved by conveyor 21 they push the trucks inadvance such as truck 25b This may continue until the entire spur isfilled with trucks or until the trucks being pushed are engaged byanother drive conveyor.

As with either of the embodiments of the invention described, truckswhich are delivered into the secondary track portion 20 stand closelybehind each other.

Where a power conveyor is provided both before and after the shunt trackportion 20, the power conveyor may comprise two different types ofdriving systems. One such system comprises circulating chains. Inanother system only one chain is used, but this chain passes out ofengagement with a truck after it reaches the shunt track portion 20, andthen re-engages that truck to draw it away from the opposite end of theshunt track portion 20.

While the invention has been described with reference to a number ofembodiments thereofit is apparent many other forms and embodiments willbe obvious to those skilled in the art in view of the foregoingdescription. Thus, the scope of the invention should not be limited bythe foregoing description but rather only by the scope of the claimsappended hereto.

I claim:

1. A tow truck system comprising a main track having a powen drivenconveyor for moving vehicles therealong, a spur intersecting said maintrack and along which vehicles may be diverted from the main track, anintermittently driven spur conveyor, said spur conveyor having a portionextending along the main track and a portion extending along the spur,said spur conveyor having arms extending outwardly therefrom for contactwith vehicles to effect intermittent movement of the spur conveyor asthe vehicles are driven by said power conveyor along that portion of themain track which overlaps said first portion of the spur conveyor.

2. A system in accordance with claim 1 including a switch controllingthe intersection between said main track and said spur, said firstportion of said spur conveyor extending from said intersection for adistance of approximately twice the length of vehicles adapted to movealong said main conveyor.

3. A system in accordance with claim 1 wherein said spur conveyor isprovided with sets of arms linearly spaced from one another at spacedpoints along the length of said spur conveyor.

4. A system in accordance with claim 3 wherein the distance between thesets of arms on said spur conveyor is approximately one half the lengthof said first portion of the spur conveyor.

5. A tow truck system comprising a main track having a power drivenconveyor for moving vehicles the realong, a spur intersecting main trackand along which vehicles may be diverted from the main track, anintermittently driven spur conveyor, said spur conveyor having a portionextending along the main track and a portion extending along the spur,said spur conveyor having arms extending outwardly therefrom for contactwith vehicles to effect intermittent movement of the spur conveyor asthe vehicles are driven by said power conveyor along that portion of themain track which overlaps said first portion of the spur conveyor, andsaid arms on said conveyor first portion extend into said main track atan elevation about the elevation of the main track power conveyor forcontact with tow pins on vehicles moving the main track.

6. A tow truck system comprising a main track having a power drivenconveyor for moving vehicles therealong, a spur intersecting said maintrack along which vehicles may be diverted from the main track, a switchcontrolling said intersection between the spur and the main track, aspur conveyor having the first portion extending along the main trackupstream from the switch and a second portion extending along said spur,said spur conveyor being an endless chain, said spur conveyor havingarms extending horizontally therefrom at spaced points therealong, thearms on said first portion of said spur conveyor extending into the maintrack at an elevation below floor level and above the elevation of saidpower driven conveyor for contact with tow pins on vehicles moving alongthe main track, whereby vehicles moving along the main track and theoverlapping portion of said spur conveyor will cause said arms tointermittently move said spur conveyor.

7. A system in accordance with claim 6 wherein said first portion ofsaid spur conveyor extends upstream along said main track for a distancecorresponding to a length greater than the length of one vehicle movingalong the main track.

8. A tow truck system comprising a main track having a power drivenconveyor for moving vehicles therealong, a spur intersecting said maintrack, an intermittently driven spur conveyor, said spur conveyor beingdisposed adjacent said spur, a plurality of outwardly directed memberssupportedby said spur conveyor for contact with vehicles to effectintermittent movement of the spur conveyors as the vehicles are drivenby said power conveyor into said spur.

9. A system in accordance with claim 8 wherein said outwardly directedmembers are held outwardly by yieldable means.

10. A system in accordance with claim 9 wherein the distance betweenadjacent outwardly directed members is at least the same as the lengthof one of said vehicles.

11. A system in accordance with claim 8 wherein drive means for saidvehicles is provided in said spur,

said drive means being spaced from said spur conveyor.

1. A tow truck system comprising a main track having a powen drivenconveyor for moving vehicles therealong, a spur intersecting said maintrack and along which vehicles may be diverted from the main track, anintermittently driven spur conveyor, said spur conveyor having a portionextending along the main track and a portion extending along the spur,said spur conveyor having arms extending outwardly therefrom for contactwith vehicles to effect intermittent movement of the spur conveyor asthe vehicles are driven by said power conveyor along that portion of themain track which overlaps said first portion of the spur conveyor.
 2. Asystem in accordance with claim 1 including a switch controlling theintersection between said main track and said spur, said first portionof said spur conveyor extending from said intersection for a distance ofapproximately twice the length of vehicles adapted to move along saidmain conveyor.
 3. A system in accordance with claim 1 wherein said spurconveyor is provided with sets of arms linearly spaced from one anotherat spaced points along the length of said spur conveyor.
 4. A system inaccordance with claim 3 wherein the distance between the sets of arms onsaid spur conveyor is approximately one half the length of said firstportion of the spur conveyor.
 5. A tow truck system comprising a maintrack having a power driven conveyor for moving vehicles therealong, aspur intersecting main track and along which vehicles may be divertedfrom the main track, an intermittently driven spur conveyor, said spurconveyor having a portion extending along the main track and a portionextending along the spur, said spur conveyor having arms extendingoutwardly therefrom for contact with vehicles to effect intermittentmovement of the spur conveyor as the vehicles are driven by said powerconveyor along that portion of the main tRack which overlaps said firstportion of the spur conveyor, and said arms on said conveyor firstportion extend into said main track at an elevation about the elevationof the main track power conveyor for contact with tow pins on vehiclesmoving the main track.
 6. A tow truck system comprising a main trackhaving a power driven conveyor for moving vehicles therealong, a spurintersecting said main track along which vehicles may be diverted fromthe main track, a switch controlling said intersection between the spurand the main track, a spur conveyor having the first portion extendingalong the main track upstream from the switch and a second portionextending along said spur, said spur conveyor being an endless chain,said spur conveyor having arms extending horizontally therefrom atspaced points therealong, the arms on said first portion of said spurconveyor extending into the main track at an elevation below floor leveland above the elevation of said power driven conveyor for contact withtow pins on vehicles moving along the main track, whereby vehiclesmoving along the main track and the overlapping portion of said spurconveyor will cause said arms to intermittently move said spur conveyor.7. A system in accordance with claim 6 wherein said first portion ofsaid spur conveyor extends upstream along said main track for a distancecorresponding to a length greater than the length of one vehicle movingalong the main track.
 8. A tow truck system comprising a main trackhaving a power driven conveyor for moving vehicles therealong, a spurintersecting said main track, an intermittently driven spur conveyor,said spur conveyor being disposed adjacent said spur, a plurality ofoutwardly directed members supported by said spur conveyor for contactwith vehicles to effect intermittent movement of the spur conveyors asthe vehicles are driven by said power conveyor into said spur.
 9. Asystem in accordance with claim 8 wherein said outwardly directedmembers are held outwardly by yieldable means.
 10. A system inaccordance with claim 9 wherein the distance between adjacent outwardlydirected members is at least the same as the length of one of saidvehicles.
 11. A system in accordance with claim 8 wherein drive meansfor said vehicles is provided in said spur, said drive means beingspaced from said spur conveyor.